Immunoregulatory abnormalities have been s own to exist in a wide variety of "autoimmune" and chronic inflammatory diseases, including systemic lupus erythematosis, chronic rheumatoid arthritis, type 1 diabetes mellitus, inflammatory bowel disease, biliary cirrhosis, uveitis, multiple schlerosis and other disorders such as crohns disease, ulcerative colitis, bullous pemphigoid, sarcoidosis, psoriasis, ichthyosis, and gravies ophthalmopathy. Although the underlying pathogenesis of each of these conditions may be quite different, they have in common the appearance of a variety of autoantibodies and self-reactive lymphocytes. Such self-reactivity may be due, in part, to a loss of the homeostatic controls under which the normal immune system operates.
Similarly, following a bone-marrow or an organ transplantation, the host lymphocytes recognize the foreign tissue antigens and begin to produce antibodies which lead to graft rejection.
The end result of an autoimmune or a rejection process is tissue destruction caused by inflammatory cells and the mediators they release. Antiinflammatory agents such as NSAID's and corticosteroids act principally by blocking the effect or secretion of these mediators but do nothing to modify the immunologic basis of the disease. On the other hand, cytotoxic agents such as cyclophosphamide, act in such a nonspecific fashion that both the normal and autoimmune responses are shut off. Indeed, patients treated with such nonspecific immunosuppressive agents are as likely to succumb from infection as they are from their autoimmune disease.
The cyclosporins are a family of immunosupressive compounds isolated from fermentation broths of various fungal species including Tolypocladium inflatum and Cylindrocarpon lucidum.
The generic structure of the class of cyclosporins has been established as a cyclic peptide which contains 11 amino acids.
For example, the structure of cyclosporin A was established as a cyclic peptide containing several methylated amino acids and at position 8 this amino acid is D-alanine which has been considered important for the biological activity of cyclosporin. ##STR1##
Generally a cyclosporin such as cyclosporin A is not cytotoxic or myelotoxic. It does not inhibit migration of monocyctes nor does it inhibit granulocytes and macrophage action. Its action is specific and leaves most established immune responses intact. However, it is nephrotoxic and is known to cause the following undesirable side effects:
(1) abnormal liver function;
(2) hirsutism;
(3) gum hypertrophy;
(4) tremor;
(5) neurotoxicity;
(6) hyperaesthesia; and
(7) gastrointestinal discomfort.
Accordingly, an object of the present invention is to provide a less nephrotoxic new cyclosporin derivative which will (1) restore the balance of the help-and-suppression mechanism of the immune system by acting at an earlier point than the anti-inflammatory agents and (2) induce specific long-term transplantation tolerance through a suppressor cell circuit without increasing the body's susceptibility to infection.
Another object of the present invention is to provide pharmaceutical compositions for administering to a patient in need of the treatment the active immunosuppressive agent of the present invention.
Still a further object of this invention is to provide a method of controlling graft rejection, autoimmune and chronic inflammatory diseases by administering a sufficient amount of the novel immunosuppressive agent in a mammalian species in need of such treatment.
Finally, it is the object of this invention to provide processes for the biosynthesis and isolation of the active compound.